This invention relates to a bicycle front wheel control mechanism equipped with a suspension system and a brake system.
FIG. 22 is a view showing the working principle of a general conventional suspension system. 1 denotes a body, 2 denotes a wheel, and 3 denotes a coil spring. This suspension system is so devised that, when the body 1 and the wheel 2 advance in the direction of arrow A to get over a bump 4 of a road surface, the coil spring 3 contracts in a vertical direction to allow the wheel 2 to move up, to thereby dampen a shock given to the body 1.
It has so far been considered that the suspension system as mentioned above has not necessarily been required for an ordinary bicycle for the following reasons:
(1) The bicycle is a vehicle which is pedaled by a rider. However, when the suspension system as mentioned above is adopted, the body 1 is then adapted to vibrate in the vertical direction because of the coil spring 3. The result is that the rider cannot pedal it with all his strength because the spring takes up some of the force which should go to the pedals. Such a phenomenon is expressed as "loss of force". PA1 (2) A part of running energy developed by the rider is consumed as vibration energy caused by the suspension system. This increases fatigue of the rider. PA1 (3) Since the ordinary bicycle does not required much speed, any shock felt by the rider is comparatively small when he pedals the bicycle on a rough road. Therefore, a suspension system is not required. PA1 (A) It will dampen not only a shock from the under side but also a shock from the front when a bicycle goes over a bump. PA1 (B) A rider can pedal a bicycle with his full strength on a flat road surface without an accompanying vertical movement of the bicycle body. PA1 (C) No part of the running energy produced by the rider is consumed by the suspension system. PA1 (D) Locking of a wheel at the time of braking can be prevented. PA1 (E) The control mechanism is simple in its structure and requires no special maintenance and inspection.
Consequently, the use of the suspension system as mentioned above is only limited to bicycles referred to as "mountain bikes" which are used for riding around hills and fields for sport.
On the other hand, airplanes and automobiles are equipped with anti-skid devices in order to prevent their wheels from locking when braking. The reason is that, when the wheel locks during braking, not only is the braking distance elongated, but steering control is lost and the body moves in a direction other than that intended by the driver, i.e., the vehicle skids, thereby resulting in a dangerous situation. Such a device for preventing the locking of the wheel at the time of braking is also necessary for a bicycle. However, an appropriate system is not yet available at present.
In recent years, the speed of bicycles has been increased. This applies also to an ordinary bicycles. The speed of a bicycle can be increased up to the speed of a motorcycle owing to the development of an ultra light-weight body and a thin high-pressure tire, and to progress in the development of multi-speed gears. In such a high-speed bicycle, any shock felt by a rider when cycling on a rough road becomes is large, but the rider endures such shock under the existing circumstances. Accordingly, there is a strong need for a suspension system for bicycles.
However, when a suspension system as shown in FIG. 22 is adopted as it is, the above-mentioned problems (1) and (2) arise. Further, maintenance and inspection are troublesome. Moreover, there is another problem. As reported by one of the present inventors in the 1975's spring science lecture meeting held by the Automobile Technology Association; when a wheel 2 is about to go over a bump 4, not only is there a shock to the wheel 2 from the bottom but there is also a shock from the front which provides a force to the wheel 2 toward the rear. In the suspension system shown in FIG. 22, however, the shock from the bottom can be dampened but the shock from the front can not be dampened, so that a shock absorbing effect is not sufficient.
On the other hand, the danger due to locking of the wheel at the time of braking increases with an increase in the speed of the bicycle. For this reason, there is a need for measures for preventing the locking of the wheels even for bicycles.
An object of this invention is to solve the above-mentioned problems and to satisfy the needs. Another object of this invention is to provide a bicycle front wheel control mechanism which can mainly satisfy the following conditions: